user: Question: WHen Jaime Aff and Christine Langner are the performers what is the subject?
Columns: ['Episode title', 'Subject', 'Music by', 'Performed by', 'First aired']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['The Body Machine', 'Nutrition and digestive system', 'Lynn Ahrens', 'Bob Dorough and Jack Sheldon', 1979.0]
SQL:

assistant: SELECT "Subject" FROM "Table" WHERE "Performed by" = 'Jaime Aff and Christine Langner';