CREATE TABLE table_20774 ("Institution" TEXT, "Location" TEXT, "Founded" FLOAT, "Affiliation" TEXT, "Enrollment" FLOAT, "Team Nickname" TEXT, "Primary conference" TEXT, "Home Rink" TEXT)

Private/Catholic school's minimum enrollment is?
SELECT MIN("Enrollment") FROM table_20774 WHERE "Affiliation" = 'Private/Catholic'
SELECT MIN("Enrollment") FROM "table_20774" WHERE "Affiliation" = 'Private/Catholic'