Question: when did grey's anatomy season 13 start
[{'answer': 'September 22 , 2016', 'provenance': [{'wikipedia_id': '50555613', 'title': "Grey's Anatomy (season 13)", 'start_paragraph_id': 52, 'start_character': 133, 'end_paragraph_id': 52, 'end_character': 152, 'bleu_score': 1.0, 'section': 'Section::::Production.:Development.\n'}]}, {'provenance': [{'wikipedia_id': '50555613', 'title': "Grey's Anatomy (season 13)", 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 418, 'bleu_score': 0.917139586014803, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7744527128929945480}, 'section': 'Section::::Abstract.'}]}]