user: Question: What couple has an average of 17.2?
Columns: ['Rank by average', 'Place', 'Couple', 'Total points', 'Number of dances', 'Average']
Types: ['real', 'real', 'text', 'real', 'real', 'text']
Sample row: [1.0, 2.0, 'Gilles & Cheryl', 449.0, 16.0, '28.1']
SQL:

assistant: SELECT "Couple" FROM "Table" WHERE "Average" = '17.2';