In Freestyle Jobs, you can see a block in the job details like:

This run spent:
5 min 19 sec waiting;
9 min 33 sec build duration;
14 min total from scheduled to completion. 

Here you can see that the three values are distinct - waiting, duration and total. If you trigger a downstream build in Pipeline and call RunWrapper.getDurationString() on it, you'll get the middle value.

However, I have noticed that for Pipeline jobs, it looks more like this:

13 min waiting;
17 min build duration;
17 min total from scheduled to completion. 

Here you can see that the "duration" includes the wait time. I would have expected to see ~4 min for build duration here. This seems to be a bug.