If your guy really cheated. I.E. Dead people voted, then you might want to take an example from the previous mayoral election in Miami. Suarez, a criminaql and complete Jackass was declared winner on election night. Well, later on it turns out his cronies voted with dead people's names, etc. The evidence piled up and his cronies one by one began ending up in Club Fed. Eventuqally, it reached court where the first judge threw out the election results in preparation for a new election. But, later on it was decided that since their were questions of Suarez's involvement that he would just be impeached from office and Corollo with the 2nd Highest Vote (Highest w/o Dead Voters) became Mayor.
But, Corollo had to go through all kinds of shit. He tried to fire the city manager who was one of Suarez's henchmen. The firing was overturned by the Commission each time. Until of course, Elian. He finally got his ass kicked out. A few months later, the Feds finally indicted his ass for Fraud and Embezzeling. I hope he rots in Prison. Unfortunately, they never got Suarez. I'm still holding out hope.