Question: who was the chairman of the union powers committee of the constituent assembly
[{'answer': 'Sachchidananda Sinha', 'provenance': [{'wikipedia_id': '1589530', 'title': 'Constituent Assembly of India', 'start_paragraph_id': 15, 'start_character': 4, 'end_paragraph_id': 15, 'end_character': 24, 'bleu_score': 1.0, 'section': 'Section::::Organization.\n'}]}, {'provenance': [{'wikipedia_id': '1589530', 'title': 'Constituent Assembly of India', 'start_paragraph_id': 15, 'start_character': 0, 'end_paragraph_id': 15, 'end_character': 615, 'bleu_score': 0.884067445879755, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15507124947052407305}, 'section': 'Section::::Organization.\n'}]}]