CREATE TABLE table_17491 ("Subjects" TEXT, "First Year" TEXT, "Second Year" TEXT, "Third Year" TEXT, "Fourth Year" TEXT)

What is the second year class following pag-unawa?
SELECT "Second Year" FROM table_17491 WHERE "First Year" = 'Pag-unawa'
SELECT "Second Year" FROM "table_17491" WHERE "First Year" = 'Pag-unawa'