user: Question: When was incumbent John N. Tillman first elected?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Arkansas 1', 'Thaddeus H. Caraway', 'Democratic', 1912.0, 'Re-elected', 'Thaddeus H. Caraway (D) Unopposed']
SQL:

assistant: SELECT "First elected" FROM "Table" WHERE "Incumbent" = 'John N. Tillman';