CREATE TABLE table_30515 ("Pick" FLOAT, "Player" TEXT, "Position" TEXT, "Nationality" TEXT, "NHL team" TEXT, "College/junior/club team" TEXT)

What is the minimum pick of a centre from the Czech Republic?
SELECT MIN("Pick") FROM table_30515 WHERE "Position" = 'Centre' AND "Nationality" = 'Czech Republic'
SELECT MIN("Pick") FROM "table_30515" WHERE "Nationality" = 'Czech Republic' AND "Position" = 'Centre'