user: Question: What is the date for a source of Result and a place of Iffendic?
Columns: ['Date', 'Place', 'Race winners', 'GP winner', 'Source']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['1 April', 'Frauenfeld', 'Ben Adriaenssen / Ben van den Bogaart', 'Ben Adriaenssen / Ben van den Bogaart', 'Result']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Source" = 'Result' AND "Place" = 'Iffendic';