The third time might be the charm for Ralph Ferrucci: The third-party candidate has announced that he will once again run against Mayor John DeStefano Jr. to hold the city’s chief executive seat — but this time, he said, he will run as an Independent. Ferrucci, 37, told the New Haven Independent on Monday that he plans to focus his campaign on saving the three senior centers to be closed because of city budget cuts. Ferrucci has run for mayor twice before, in 2003 and 2007. This past November, he challenged U.S. Rep. Rosa DeLauro. No other candidates have announced plans to challenge DeStefano in November.