Profiler TextData output is null
EventClass 15 is "Audit Logout" there's no TextData to associate with that. It's simply the connection closing. TextData would only be associated with events like "SQL:StmtStarting", etc... 

See here for more info: http://weblogs.sqlteam.com/mladenp/archive/2007/11/09/Map-SQL-Server-Profiler-EventClass-ID-to-its-name-in.aspx

From comments: The duration it shows in the log is the total connection duration.