Question: how many episodes in the first season of doctor who
[{'answer': '13', 'provenance': [{'wikipedia_id': '18012738', 'title': 'Doctor Who (series 1)', 'start_paragraph_id': 1, 'start_character': 628, 'end_paragraph_id': 1, 'end_character': 630, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]