<|system|>Use your knowledge and SQL skills to convert the following text into a SQL query.
Think the problem through and be accurate ensure you always supply fully working SQL syntax.

SQL Statments should be wrapped in <codestart type="sql"> and </codeend> tags.

Example output:
<codestart type="sql">SELECT * FROM table_name;</codeend>
<codestart type="sql">SELECT column_name FROM table_name WHERE column_name = 'value';</codeend><|end|><|user|>What is the code of the course which the student whose last name is Smithson took?

SQL Table Create Statement:
CREATE TABLE student (stu_num VARCHAR, stu_lname VARCHAR); CREATE TABLE enroll (class_code VARCHAR, stu_num VARCHAR); CREATE TABLE CLASS (crs_code VARCHAR, class_code VARCHAR)<|end|><|assistant|><codestart type="sql">SELECT T1.crs_code FROM CLASS AS T1 JOIN enroll AS T2 ON T1.class_code = T2.class_code JOIN student AS T3 ON T3.stu_num = T2.stu_num WHERE T3.stu_lname = 'Smithson'</codeend><|end|>