Question: who plays the mayor's assistant on blue bloods
[{'answer': 'Mark Linn - Baker', 'provenance': [{'wikipedia_id': '47422881', 'title': 'List of Blue Bloods characters', 'start_paragraph_id': 136, 'start_character': 62, 'end_paragraph_id': 136, 'end_character': 78, 'bleu_score': 1.0, 'section': 'Section::::Recurring characters.:Associates of Frank.:Margaret Dutton.\n'}]}]