The DUP has failed in its attempt to delay legislation to end double-jobbing between the assembly and local councils.
The party had tried to amend the Local Government Disqualification Bill until 2014 or until the assembly reduces the number of councils to 11.
MLAs spend most of the day debating the Bill but when it came to the vote the DUP's amendments failed to get through.
The assembly was debating the further consideration stage of the bill on Tuesday.
East Belfast MLA Dawn Purvis wants the ban to come into force in time for next May's Stormont and council elections.