user: Question: What district is the incumbent Republican and the incumbent Retired to run for Governor Democratic gain?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Results']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['Colorado 1', 'Diana DeGette', 'Democratic', 1996.0, 'Re-elected']
SQL:

assistant: SELECT "District" FROM "Table" WHERE "Party" = 'Republican' AND "Results" = 'Retired to run for Governor Democratic gain';