LaSalle Bank is reaping the rewards of its investment as the official bank of the Chicago White Sox as the World Series between the Sox and the Houston Astros opened Saturday at U.S. Cellular Field. But LaSalle might not be able to expect much free television advertising time as the bank's sign sits some 400 feet away from home plate in deep right field. With the way both staffs have been pitching, a home run blast that would travel that far might be more than just a long shot.