Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_18333678_2 (operator VARCHAR, arrival VARCHAR)

### Question ###
what is the operator of trains arriving at 13.39 

### Accurate SQL ###

SELECT operator FROM table_18333678_2 WHERE arrival = "13.39"