SOFIA, Oct 12 (Reuters) - Bulgaria"s centre-right GERB party leads its rivals ahead of the country"s third parliamentary election this year, although anger against corruption put an end to its almost decade in power in April, a new opinion poll showed on Tuesday. Bulgarians will vote again on Nov. 14 after inconclusive elections in April and July failed to produce a government. read more Anger against high-level graft in the European Union"s poorest country unseated GERB from office after the April vote, but its political opponents could not agree on a government after either of the April and July polls. Former premier Boyko Borissov"s GERB garnered 23.1% support, slightly below the 23.5% it won in July, when it came as a very close second, the opinion poll by Sofia-based Alpha Research showed. The opposition Socialists are gaining support but still remain a distant second with 16.8% backing, up from 13.4% in the July election, showed the survey, which was conducted from Oct 4 to 10 among 1,123 people. A new centrist party, We Are Continuing the Change, set up by two popular former interim ministers, appeared as the third most popular faction with 15.9% support, the survey showed. read more Backing for the anti-establishment ITN party of TV talk show host and singer Slavi Trifonov, which won July election with 24.1%, has plunged to 10.4%, with many Bulgarians disappointed with its failure to forge a coalition government. Two other factions are seen entering Bulgaria"s next parliament, but neither party will win an outright majority. A coalition of three to four parties will be needed for a majority government, Alpha Research said. Bulgarians will also vote to choose a new president on Nov. 14, with incumbent Rumen Radev, a harsh critic of Borissov, seen as a front-runner at the first round for the largely ceremonial post, the survey showed.