user: ### NOW ANSWER:
Question: When the result is Retired to run for U.S. Senate Democratic hold, who is the candidate?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Texas 1', 'Wright Patman', 'Democratic', 1928.0, 'Re-elected', 'Wright Patman (D) Unopposed']
SQL:

assistant: SELECT "Candidates" FROM "Table" WHERE "Result" = 'Retired to run for U.S. Senate Democratic hold';