ocr: 1998 may seem a long way off, but Sen. Alfonse M. D'Amato may be thinking about his future. Not that anyone really believes the freshmen in Congress will get term limits legislation through; Sen. D' Amato's challenge may be New Yock' * S Republican Lt. Gov. Elizabeth Nccaughey. Democratic sources say the senator is trying to force Ms. McCaughey from her job and that she, in turn, is considering a ru for the Senate. Guess whose seat she wants? Remarkably, Al D'. Amato has eluded political enemies, campaign opponents, media critics and everyone else who has tried to pin evidence of his sleaze on ...