Duration unit in SQL Server trace file I have generated a trace file in SQL Server 2012, not really sure about the unit of duration, it is measured by millisecond?
As CPU is in milliseconds.From the beginning with SQL Server 2005, the server reports the duration of an event in microseconds (one millionth, or 10-6 of a second) and the amount of CPU time used by the event in milliseconds (one thousandth, or 10-3 of a second). Even in SQL Server 2000, the server reported both duration and CPU time in milliseconds. In SQL Server 2005 and later, the SQL Server Profiler graphical user interface displays the Duration column in milliseconds by default, but when a trace is saved to either a file or a database table, the Duration column value is written in microseconds.

For your further ref Interpreting CPU Utilization for Performance Analysis and Here