CREATE TABLE table_name_1 (quantity INT, class_from_1928 VARCHAR)

What's the sum of Quantity for the Class of 1928 of CI-30?
SELECT SUM(quantity) FROM table_name_1 WHERE class_from_1928 = "ci-30"
SELECT SUM("quantity") FROM "table_name_1" WHERE "ci-30" = "class_from_1928"