user: Question: Who became the champion for the 1984 Grand Prix where Marty Davis was the runner-up?
Columns: ['Week of', 'Tournament', 'Champion', 'Runner-up', 'Semifinalists', 'Quarterfinalists']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['6 August', 'Cleveland , Ohio, USA Hard', 'Terry Moor 3-6, 7-6, 6-2', 'Marty Davis', 'Matt Mitchell Jeff Klaparda', 'David Dowlen David Pate Greg Holmes Mike De Palmer']
SQL:

assistant: SELECT "Champion" FROM "Table" WHERE "Runner-up" = 'Marty Davis';