user: Question: Which Chief Judge has Active service of 1873–1875?
Columns: ['State', 'Born/Died', 'Active service', 'Chief Judge', 'Senior status', 'Appointed by', 'Reason for termination']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['WI', '1801–1874', '1870–1873 Reassigned from District of Wisconsin', '—', '—', 'Polk Category:Articles with hCards', 'retirement']
SQL:

assistant: SELECT "Chief Judge" FROM "Table" WHERE "Active service" = '1873–1875';