user: Question: Which Effective date has a Where of Illinois, and Affected area codes of 217?
Columns: ['New area code', 'Where', 'Affected area codes', 'Format', 'Effective date']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [227.0, 'Maryland', '240, 301', 'Overlay', 'None']
SQL:

assistant: SELECT "Effective date" FROM "Table" WHERE "Where" = 'Illinois' AND "Affected area codes" = '217';