Securities and Exchange Commission Chairman Mary Schapiro told lawmakers Thursday that pending legislation to remove a provision that allows the agency to refuse some document requests could harm the SEC’s ability to police the financial entities it regulates. Several bills have been filed in Congress seeking to strip out the controversial provision, which was included in the Dodd-Frank financial-overhaul law enacted in July. But Schapiro said all of the pending bills would “diminish” the agency’s ability to carry out its examination duties.