CREATE TABLE table_name_79 (enrollment INT, year_joined VARCHAR, location VARCHAR)

what is the enrollement for the year joined 1958 in clarksville?
SELECT SUM(enrollment) FROM table_name_79 WHERE year_joined = 1958 AND location = "clarksville"
SELECT SUM("enrollment") FROM "table_name_79" WHERE "clarksville" = "location" AND "year_joined" = 1958