Question: when is the senate run off in alabama
[{'answer': 'December 12 , 2017', 'provenance': [{'wikipedia_id': '52878007', 'title': '2017 United States Senate special election in Alabama', 'start_paragraph_id': 2, 'start_character': 370, 'end_paragraph_id': 2, 'end_character': 388, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]