Question: who is the demon who killed sam and dean's mom
[{'answer': 'Azazel', 'provenance': [{'wikipedia_id': '7488378', 'title': 'Azazel (Supernatural)', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 6, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '7488378', 'title': 'Azazel (Supernatural)', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 361, 'bleu_score': 0.968982777549629, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 564853780780936853}, 'section': 'Section::::Plot.\n'}]}]