how many incumbent with first elected being 1924
{'header': ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates'], 'page_title': 'United States House of Representatives elections, 1924', 'page_id': '', 'types': ['text', 'text', 'text', 'real', 'text', 'text'], 'id': '1-1342393-17', 'section_title': '', 'caption': '', 'rows': [['Louisiana 1', "James O'Connor", 'Democratic', '1918', 'Re-elected', "James O'Connor (D) Unopposed"], ['Louisiana 2', 'James Zacharie Spearing', 'Democratic', '1924', 'Re-elected', 'James Zacharie Spearing (D) Unopposed'], ['Louisiana 3', 'Whitmell P. Martin', 'Democratic', '1914', 'Re-elected', 'Whitmell P. Martin (D) Unopposed'], ['Louisiana 4', 'John N. Sandlin', 'Democratic', '1920', 'Re-elected', 'John N. Sandlin (D) Unopposed'], ['Louisiana 5', 'Riley Joseph Wilson', 'Democratic', '1914', 'Re-elected', 'Riley Joseph Wilson (D) Unopposed'], ['Louisiana 6', 'George K. Favrot', 'Democratic', '1920', 'Lost renomination Democratic hold', 'Bolivar E. Kemp (D) Unopposed'], ['Louisiana 7', 'Ladislas Lazaro', 'Democratic', '1912', 'Re-elected', 'Ladislas Lazaro (D) Unopposed']], 'name': 'table_1342393_17'}