Question: when does lexie come on grey's anatomy
[{'answer': 'season three', 'provenance': [{'wikipedia_id': '11340577', 'title': 'Lexie Grey', 'start_paragraph_id': 1, 'start_character': 232, 'end_paragraph_id': 1, 'end_character': 244, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]