user: Question: What were the sales for DJ Casper when he was in a position lower than 13?
Columns: ['Position', 'Song Title', 'Artist', 'Sales', 'Highest Position']
Types: ['real', 'text', 'text', 'real', 'real']
Sample row: [1.0, "Do They Know It's Christmas", 'Band Aid 20', 1094000.0, 1.0]
SQL:

assistant: SELECT "Sales" FROM "Table" WHERE "Position" < 13.0 AND "Artist" = 'DJ Casper';