Question: when did the last season of dexter air
[{'answer': '2013', 'provenance': [{'wikipedia_id': '5981816', 'title': 'Dexter (TV series)', 'start_paragraph_id': 1, 'start_character': 122, 'end_paragraph_id': 1, 'end_character': 126, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '5981816', 'title': 'Dexter (TV series)', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 378, 'bleu_score': 0.914208565914368, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6558792054775134455}, 'section': 'Section::::Abstract.'}]}]