Question: when did the first episode of law and order svu air
[{'answer': 'September 20 , 1999', 'provenance': [{'wikipedia_id': '9860643', 'title': 'Law & Order: Special Victims Unit (season 1)', 'start_paragraph_id': 1, 'start_character': 64, 'end_paragraph_id': 1, 'end_character': 85, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '9860643', 'title': 'Law & Order: Special Victims Unit (season 1)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 543, 'bleu_score': 0.8369245142765611, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 186967519665499502}, 'section': 'Section::::Abstract.'}]}]