What's the year of the first election of the district whose incumbent is Edwin E. Willis?
{'header': ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates'], 'page_title': 'United States House of Representatives elections, 1966', 'section_title': '', 'caption': '', 'rows': [['Louisiana 1', 'F. Edward Hebert', 'Democratic', '1940', 'Re-elected', 'F. Edward Hebert (D) Unopposed'], ['Louisiana 2', 'Hale Boggs', 'Democratic', '1946', 'Re-elected', 'Hale Boggs (D) 68.6% Leonard L. Limes (R) 31.4%'], ['Louisiana 3', 'Edwin E. Willis', 'Democratic', '1948', 'Re-elected', 'Edwin E. Willis (D) 59.7% Hall M. Lyons (R) 40.3%'], ['Louisiana 4', 'Joe Waggonner', 'Democratic', '1961', 'Re-elected', 'Joe Waggonner (D) Unopposed'], ['Louisiana 5', 'Otto Passman', 'Democratic', '1946', 'Re-elected', 'Otto Passman (D) Unopposed'], ['Louisiana 6', 'James H. Morrison', 'Democratic', '1942', 'Lost renomination Democratic hold', 'John Rarick (D) 76.6% Crayton G. Hall (R) 23.4%'], ['Louisiana 7', 'Edwin Edwards', 'Democratic', '1965', 'Re-elected', 'Edwin Edwards (D) Unopposed']]}