Those are ODBC escape sequences for date constants. The DBMS does not recognize that syntax, but if you are using a tool that requires its use, the ODBC driver can parse the query and translate it to supported Teradata syntax. Parsing is enabled by default when you install the driver. Generally I advise people to disable it, because it can have other side effects - like modifying DDL as well as DML - and can cause some confusion since the SQL the database receives isn't always exactly what you thought you sent.
But since it appears you need this feature, double check your ODBC setup to be sure it is enabled:
In a UNIX/Linux .ini file, the option is called NoScan; you can just be sure NoScan is omitted or you can explicitly set NoScan=No. I recommend you also set DateTimeFormat=AAA (not the default III).
In Windows, the option is called Disable Parsing; you should make sure the box is un-checked, and again I'd recommend setting DateTimeFormat=AAA.
In SQL Assistant, the driver setting is overridden by the Query option "Allow use of ODBC SQL Extensions in queries"; be sure the box is checked if you need to submit ODBC escape sequences.