Table schema:
CREATE TABLE Ref_Detention_Type (detention_type_description VARCHAR, detention_type_code VARCHAR); CREATE TABLE Detention (detention_type_code VARCHAR)

Question: What are the code and description of the least frequent detention type ?
SQL: SELECT T1.detention_type_code, T2.detention_type_description FROM Detention AS T1 JOIN Ref_Detention_Type AS T2 ON T1.detention_type_code = T2.detention_type_code GROUP BY T1.detention_type_code ORDER BY COUNT(*) LIMIT 1