Lights, Camera . . . Cue the Speaker: Assembly Speaker Willie Brown said the single line he speaks in Francis Ford Coppola's upcoming "Godfather III" is "sufficient for my (movie) debut." The San Francisco Democrat spent a long weekend in Rome doing a scene with Al Pacino. Brown was hired when Coppola told the actor originally chosen for the part of a black politician, "Why can't you act more like Willie Brown?" and then demanded: "Get me Willie Brown!" Asked if his career is following the reverse course of an actor named Ronald Reagan, Brown replied, "If I could be as successful, I wouldn't mind it."