Hello @anon43108023 & @anon85153177
This is a very valid request and one that we have been asking for for a while.
Currently, there is a workaround, while it is a bit manual, will def do the intended outcome and will be a better reflection for what you are after.
I have a custom field on my projects called Hours, it is a numeric field. Assignees are asked to fill it in when working on a task. In the end, you can report on the total number off hours from that custom field.
and here is a product feedback you may wish to upvote: Please build time tracking into Asana
There are some integrations you can get with asana to help track the time of work on tasks.
Check them out here like this one for example:
Hope this helps.