Question: who availed the longest term as president of indian national congress
[{'answer': 'Sonia Gandhi', 'provenance': [{'wikipedia_id': '2012055', 'title': 'List of Presidents of the Indian National Congress', 'start_paragraph_id': 5, 'start_character': 297, 'end_paragraph_id': 5, 'end_character': 309, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '2012055', 'title': 'List of Presidents of the Indian National Congress', 'start_paragraph_id': 5, 'start_character': 14, 'end_paragraph_id': 5, 'end_character': 440, 'bleu_score': 0.8231291484646841, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5477419555148853596}, 'section': 'Section::::History.\n'}]}]