The AH table contains entries that have reached a certain point in processing and hold all job history, so you can identify jobs that have been running over any X time or X times the ERT, etc. Jobs with the longest average runtime over the last 60 days with at least 6 instances and only those with a successful completion.
For current activity, you can either set a filter in the Activity Panel to only show jobs/flows etc that were started or activated prior to a specific time (more than 2 hours ago).
The EH table is the primary source for the Activity Panel, and has columns SIMILAR (not identical) to the AH table. This would be a better source for running activity than AH, if the activity panel option does not work.