user: Question: What is the tenure of the person whose courtesy title is Yamashiro-no-kami?
Columns: ['Name', 'Tenure', 'Courtesy title', 'Court Rank', 'revenues']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Naitō Masamitsu ( 内藤政苗 ? )', '1749–1766', 'Tamba-no-kami', 'Lower 5th (従五位下)', '20,000 koku']
SQL:

assistant: SELECT "Tenure" FROM "Table" WHERE "Courtesy title" = 'Yamashiro-no-kami';