Who were the candidates when Noble Jones Gregory was incumbent?
{'header': ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates'], 'page_title': 'United States House of Representatives elections, 1940', 'page_id': '', 'types': ['text', 'text', 'text', 'real', 'text', 'text'], 'id': '1-1342270-17', 'section_title': '', 'caption': '', 'rows': [['Kentucky 1', 'Noble Jones Gregory', 'Democratic', '1936', 'Re-elected', 'Noble Jones Gregory (D) Unopposed'], ['Kentucky 2', 'Beverly M. Vincent', 'Democratic', '1937', 'Re-elected', 'Beverly M. Vincent (D) Unopposed'], ['Kentucky 3', "Emmet O'Neal", 'Democratic', '1934', 'Re-elected', "Emmet O'Neal (D) 60.0% Ben J. Brumleve (R) 40.0%"], ['Kentucky 5', 'Brent Spence', 'Democratic', '1930', 'Re-elected', 'Brent Spence (D) 61.2% Henry J. Cook (R) 38.8%'], ['Kentucky 7', 'Andrew J. May', 'Democratic', '1930', 'Re-elected', 'Andrew J. May (D) 56.8% James W. Turner (R) 43.2%'], ['Kentucky 8', 'Joe B. Bates', 'Democratic', '1930', 'Re-elected', 'Joe B. Bates (D) 58.0% H. Clell Hayes (R) 42.0%']], 'name': 'table_1342270_17'}