Question: how many episodes are there in season 1 of riverdale
[{'answer': '13', 'provenance': [{'wikipedia_id': '49281386', 'title': 'Riverdale (2017 TV series)', 'start_paragraph_id': 23, 'start_character': 64, 'end_paragraph_id': 23, 'end_character': 66, 'bleu_score': 1.0, 'section': 'Section::::Production.:Development.\n'}]}]