Question: who was the first person to be legally executed using an electric chair
[{'answer': 'William Francis Kemmler', 'provenance': [{'wikipedia_id': '303301', 'title': 'William Kemmler', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 23, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '303301', 'title': 'William Kemmler', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 274, 'bleu_score': 0.535063924562165, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8425319452909809020}, 'section': 'Section::::Abstract.'}]}]