Question: who has held the office of chief minister of the longest time
[{'answer': 'Pawan Chamling', 'provenance': [{'wikipedia_id': '1509671', 'title': 'Pawan Kumar Chamling', 'start_paragraph_id': 4, 'start_character': 251, 'end_paragraph_id': 4, 'end_character': 265, 'bleu_score': 1.0, 'section': 'Section::::Personal life.\n'}]}, {'provenance': [{'wikipedia_id': '1509671', 'title': 'Pawan Kumar Chamling', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 237, 'bleu_score': 0.6215018619054531, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18017709444759248652}, 'section': 'Section::::Abstract.'}]}]