user: Question: What's the tenure of 3rd son of Tadatsune?
Columns: ['Name', 'Tenure', 'Courtesy title', 'Court Rank', 'Revenues', 'Lineage']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Ōoka Tadasuke (大岡忠相)', '1748–1751', 'Echizen-no-kami (越前守)', 'Lower 5th (従五位下)', '10,000 koku', '4th son of hatamoto Ōoka Tadataka']
SQL:

assistant: SELECT "Tenure" FROM "Table" WHERE "Lineage" = '3rd son of Tadatsune';