Deborah Orin-Eilbeck, The Post's longtime D.C. bureau chief whose passion for politics and unrivaled integrity kept Washington on its toes, died yesterday after a battle with cancer. "Laura and I were saddened to learn of the death of Deborah Orin-Eilbeck," President Bush said. "Deb had a distinguished, decades-long career as a journalist, covering every presidential campaign since 1980 and joining the New York Post's Washington bureau in 1988. "Deb fought a valiant battle against cancer with the same tenacity, devotion, and determination that she brought to her work in the White House briefing room through numerous administrations," the president said....