Question: when was the defense of marriage act passed
[{'answer': 'September 21 , 1996', 'provenance': [{'wikipedia_id': '92946', 'title': 'Defense of Marriage Act', 'start_paragraph_id': 20, 'start_character': 699, 'end_paragraph_id': 20, 'end_character': 718, 'bleu_score': 1.0, 'section': 'Section::::Enactment and role of President Clinton.\n'}]}]