user: Question: Which Nationality has a Position of Defense, and a Player of Nikita Korovkin?
Columns: ['Round', 'Player', 'Position', 'Nationality', 'College/Junior/Club Team (League)']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Joni Pitkanen', 'Defense', 'Finland', 'Karpat ( SM-liiga )']
SQL:

assistant: SELECT "Nationality" FROM "Table" WHERE "Position" = 'Defense' AND "Player" = 'Nikita Korovkin';