Congressional leaders took their latest step Tuesday toward passing sweeping bank-reform legislation by picking 12 senators — seven Democrats and five Republicans — to participate in efforts to reconcile the financial-industry regulation bills approved by the House and Senate. Senate leadership excluded controversial senators from the effort by approving Democratic Sens. Christopher Dodd of Connecticut, chairman of the Senate Banking Committee; Tim Johnson of South Dakota; Jack Reed of Rhode Island; and Charles Schumer of New York, while the Republican senators chosen to participate are Richard Shelby of Alabama, the Banking Committee’s ranking member; Bob Corker of Tennessee; Mike Crapo of Idaho; and Judd Gregg of New Hampshire.