user: Question: What is the tenure of the person with revenues of 60,000-->58,000 koku?
Columns: ['Name', 'Tenure', 'Courtesy title', 'Court Rank', 'revenues']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Kuze Shigeyuki ( 久世重之 ? )', '1705–1720', 'Yamato-no-kami', 'Lower 4th (従四位下)', '50,000 koku']
SQL:

assistant: SELECT "Tenure" FROM "Table" WHERE "revenues" = '60,000-->58,000 koku';