Question: who plays the president's son on designated survivor
[{'answer': 'Tanner Buchanan', 'provenance': [{'wikipedia_id': '49016781', 'title': 'Designated Survivor (TV series)', 'start_paragraph_id': 29, 'start_character': 485, 'end_paragraph_id': 29, 'end_character': 500, 'bleu_score': 1.0, 'section': 'Section::::Production.:Casting.\n'}]}]