Mario Cuomo famously refused to sit for a portrait to hang in Albany’s Hall of Governors, saying it was too pretentious, but he finally allowed painter Simmie Knox to create one from a 1989 photo. But portrait-shy Mario said at a ceremony to unveil the work that he can’t wait for his son’s picture to hang near his. After Gov. Andrew Cuomo dedicated the painting by calling his “wincing” (spies said) dad “the cherry on the cake,” he added, “I’m sorry we have only one microphone . . . and I’ve got it. It’s nice to be the governor.” After the unveiling, Mario told broadcaster Bill O’Shaughnessy: “I want to be there for Andrew’s ‘hanging’ . . . that’s the greatest wish Matilda and I have . . . that we’ll be there to witness it.”