When was incumbent John N. Tillman first elected?
{'header': ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates'], 'page_title': 'United States House of Representatives elections, 1918', 'section_title': '', 'caption': '', 'rows': [['Arkansas 1', 'Thaddeus H. Caraway', 'Democratic', '1912', 'Re-elected', 'Thaddeus H. Caraway (D) Unopposed'], ['Arkansas 2', 'William A. Oldfield', 'Democratic', '1908', 'Re-elected', 'William A. Oldfield (D) Unopposed'], ['Arkansas 3', 'John N. Tillman', 'Democratic', '1914', 'Re-elected', 'John N. Tillman (D) Unopposed'], ['Arkansas 4', 'Otis Wingo', 'Democratic', '1912', 'Re-elected', 'Otis Wingo (D) Unopposed'], ['Arkansas 5', 'Henderson M. Jacoway', 'Democratic', '1910', 'Re-elected', 'Henderson M. Jacoway (D) Unopposed'], ['Arkansas 6', 'Samuel M. Taylor', 'Democratic', '1913', 'Re-elected', 'Samuel M. Taylor (D) Unopposed']]}