user: Question: What district is incumbent Sid Simpson from?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Illinois 3', 'Edward A. Kelly', 'Democratic', 1944.0, 'Lost re-election Republican gain', 'Fred E. Busbey (R) 57.2% Edward A. Kelly (D) 42.8%']
SQL:

assistant: SELECT "District" FROM "Table" WHERE "Incumbent" = 'Sid Simpson';