[oracle] String to date in Oracle with milliseconds

I want to convert the follow string to date:

2004-09-30 23:53:48,140000000

I tried:

to_date('#', 'YYYY-MM-DD HH24:MI:SS,FF9')

But PL/SQL keep throwing this error:

ORA-01821: date format not recognized.

FF9 is incorrect for Oracle, any suggestion?

I don't think you can use fractional seconds with to_date or the DATE type in Oracle. I think you need to_timestamp which returns a TIMESTAMP type.