In a rare move, a federal judge appointed a lawyer to defend an ill and “nearly destitute” man against a lawsuit filed in a business dispute. In a written opinion Monday, U.S. Magistrate Judge Iain D. Johnston conceded that it’s unusual to assign counsel to represent a defendant in a civil case. Much more often, he wrote, attorneys are tapped under local court rules to represent plaintiffs who are pursuing suits. But defendant David Clements’ situation is unusual, Johnston wrote. Although …