user: Question: What dance was leeza gibbons the worst dancer for, receiving a score lower than 15?
Columns: ['Dance', 'Best dancer', 'Best score', 'Worst dancer', 'Worst score']
Types: ['text', 'text', 'real', 'text', 'real']
Sample row: ['Cha-cha-cha', 'Laila Ali', 30.0, 'Billy Ray Cyrus', 13.0]
SQL:

assistant: SELECT "Best score" FROM "Table" WHERE "Worst dancer" = 'leeza gibbons' AND "Worst score" < 15.0;