PostgreSQL reports an error when creating a trigger,

CREATE FUNCTION jins_xfupdate_func() RETURNS TRIGGER AS
$$
DECLARE
BEGIN
IF NEW.js_ achievement 01>=60 AND OLD. js_ achievement 01<60 THEN
UPDATE "jins_ Student 01" set js_ Total credits completed 01= js_ Total credits completed 01+(SELECT js_ credits 01 FROM "jins_ Course 01" WHERE js_ Course number 01=NEW.js_ Course number 01)
WHERE "jins_ Student 01".js_ Student number 01=NEW. js_ Student number 01;
RETURN NEW;
ELSE RETURN NULL;
END IF;
END
$$LANGUAGE PLPGSQL;

CREATE TRIGGER jins_TG Credit statistics trigger
AFTER UPDATE ON jins_ Study 01"
FOR EACH ROW
EXECUTE PROCEDURE jins_xfupdate_func();