A federal judge should have stepped aside from a challenge to a sentence she imposed during an earlier stint on the Indiana state bench, an appeals court ruled Wednesday.The 7th U.S. Circuit Court of Appeals wrote that reasonable people would doubt the impartiality of a former state judge who passes judgment on his or her own decision.Therefore, the court held, federal judges are always disqualified from hearing collateral attacks on judgments they entered or affirmed while serving as state judges.Overturning its own …