It’s not often a single investor owns one of the city’s top trophy penthouses in both New York and Miami — and puts them both on the market at the same time for a combined $138 million. William Duker, a former lawyer turned investor, has listed his Miami penthouse triplex at the Apogee, 800 South Pointe, for $78 million. At the same time, he’s put his Tribeca penthouse at the Sky Lofts, 145 Hudson St., on the market for $59.5 million, Gimme Shelter has learned. “I’m 72, and I’m just beginning