user: Question: What year was incumbent William F. Stevenson first elected?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['South Carolina 1', 'Richard S. Whaley', 'Democratic', 1913.0, 'Retired Democratic hold', 'W. Turner Logan (D) 92.6% ? Saspartas (I) 7.4%']
SQL:

assistant: SELECT "First elected" FROM "Table" WHERE "Incumbent" = 'William F. Stevenson';