user: Question: In what district was Keith Ellison the incumbent?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Minnesota 1', 'Tim Walz', 'Democratic', 2006.0, 'Re-elected', 'Tim Walz (D) 57.6% Allen Quist (R) 42.4%']
SQL:

assistant: SELECT "District" FROM "Table" WHERE "Incumbent" = 'Keith Ellison';