Question: who was the ex-officio chairman of the rajya sabha
[{'answer': 'Venkaiah Naidu', 'provenance': [{'wikipedia_id': '232210', 'title': 'Rajya Sabha', 'start_paragraph_id': 2, 'start_character': 349, 'end_paragraph_id': 2, 'end_character': 363, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '232210', 'title': 'Rajya Sabha', 'start_paragraph_id': 2, 'start_character': 187, 'end_paragraph_id': 2, 'end_character': 651, 'bleu_score': 0.7160940267789101, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4367759757680275648}, 'section': 'Section::::Abstract.'}]}]