Question: when did the pittsburgh steelers win their first super bowl
[{'answer': '1974', 'provenance': [{'wikipedia_id': '23338', 'title': 'Pittsburgh Steelers', 'start_paragraph_id': 10, 'start_character': 341, 'end_paragraph_id': 10, 'end_character': 345, 'bleu_score': 1.0, 'section': 'Section::::Franchise history.:The Chuck Noll era.\n'}]}]