ST. PETERSBURG -- The democrats, disorganized as always, appear to be heading for disaster in St. Petersburg's city elections this Sunday, while Communists and nationalists are counting on profiting from the split among their opponents.


About 750 candidates are running for the new 50-seat City Assembly. Most are drawn from a confusing stew of 16 parties, among which only three are readily recognizable: Vladimir Zhirinovsky's Liberal Democratic Party, the Communist Party and Great Russia, a coalition of nationalists.


The other parties have been created in the past three months and have say-nothing names like Beloved City, All Petersburg, Business Petersburg, and Democratic Union of Petersburg.


Some of these parties are reworked local versions of Russia's Choice and other democratic parties, which performed miserably in December's elections to Russia's State Duma; others are not. And for many voters, polls indicate, it will be easier to stay at home than to sort out the difference.


"Sixty-five percent of the city would like to support the democrats, if they could only find them," said Maria Matskevich, a researcher at the Center for Research and Prognosis of Social Processes, which monitors local and national politics.


"If, as in December, six or seven candidates of democratic orientation divide among themselves 50 or 60 percent of the votes in each district, then candidates from the LDPR, Russian Party and the Communists can pretty confidently count upon slipping in."


The City Assembly replaces the 398-seat City Soviet, which was swept aside in the wake of Moscow's October riots. If pro-democracy forces lose out here, it will change the tone of political life in Russia's second city, which has been a stronghold of democratic and economic reform.


A democratic loss would also be yet another blow to the prestige of President Boris Yeltsin and his government, and would hammer the last nail into the political coffin of Mayor Anatoly Sobchak, a Western-oriented reformer elected in 1991 who has fallen off the political map with startling speed.


The Center for Research and Prognosis of Social Processes predicts a turnout of 40 percent -- and possibly much less, depending on the weather. Meanwhile, 55 percent of those Petersburgers who say they might vote still have not made up their minds whom to vote for, according to polls by the center.


Among those 45 percent who have made up their minds, 19 percent support Alexander Belyayev, former chairman of the City Soviet, one of St. Petersburg's deputies to the State Duma and a rising political star. Belyayev's party, Democratic Union of Petersburg, is the leading democratic party, and is strongly backed by luminaries such as physicist Nikita Tolstoy, historian Daniil Granin and writer Mikhail Chulaki.


Twenty-three percent are for Zhirinovsky, 13 percent for the nationalist coalition Great Russia and 9 percent for the Communists, according to the poll of 2,500 people in the first week of March.


Sobchak was once rated Russia's third most popular politician, after President Boris Yeltsin and Mikhail Gorbachev, the former Soviet president. In September 1991, he enjoyed the support of nearly 70 percent of his city.


But by June 1992 his popularity had slipped to 23 percent, where it has hovered ever since. His term does not end until 1996, but 31 percent of Petersburgers support holding immediate mayoral elections -- a decision that would probably rest with the new City Assembly. In the past month journalists and politicians have been almost unanimous in deriding the mayor as a has-been, and the local newspapers are filled with speculation about his replacement.


"The mayor still exists. He meets with the president. He's greeted happily by high-ranking foreign politicians. But in the plans of the city's political and business elite, he is already a figure of yesterday," wrote Dmitry Travin, political observer for Echo, one of St. Petersburg's leading newspapers.