AS Fitzgerald might have said, people who live on hills are different from you and me. From Murray Hill to Carnegie Hill in Manhattan, from Brooklyn Heights to Park Slope in Brooklyn, New Yorkers with cash to spend have long sought the high ground. In Staten Island, Todt Hill is a coveted area, as are Grymes Hill and Dongan Hills Colony. But for all its elevation, Ward Hill, on the island’s north shore, has managed to remain below the radar.