Explanation
Monitor activity runs. To get a detailed view of the individual activity runs of a specific pipeline run, click on the pipeline name.
Example:

The list view shows activity runs that correspond to each pipeline run. Hover over the specific activity run to get run-specific information such as the JSON input, JSON output, and detailed activity-specific monitoring experiences.

You can check the Duration.
Reference:
https://docs.microsoft.com/en-us/azure/data-factory/monitor-visually