user: Question: What is the election date for those politicians who left office on 1850-11-15?
Columns: ['Election number', 'Election date', 'District', 'Province', 'Took office', 'Left office']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [9.0, '1837-9-22', 'At large', 'Seville', '1837-12-19', '1839-06-01']
SQL:

assistant: SELECT "Election date" FROM "Table" WHERE "Left office" = '1850-11-15';