CREATE TABLE table_64927 ("Event" TEXT, "Date" TEXT, "Location" TEXT, "Winning skip" TEXT, "Runner-up skip" TEXT)

What's the location of the National event with Kevin Martin winning?
SELECT "Location" FROM table_64927 WHERE "Winning skip" = 'kevin martin' AND "Event" = 'the national'
SELECT "Location" FROM "table_64927" WHERE "Event" = 'the national' AND "Winning skip" = 'kevin martin'