Question: what episode does supergirl go on the flash
[{'answer': 'Duet', 'provenance': [{'wikipedia_id': '53517522', 'title': 'Duet (The Flash)', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 4, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '53517522', 'title': 'Duet (The Flash)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 910, 'bleu_score': 0.9469616891680981, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11958684793686891320}, 'section': 'Section::::Abstract.'}]}]