How to make a column in a report to only shows the agent name who firstly solve the incident?

Summary:

I have a report to shows solved incident and agent name who solve it, but sometimes incidents reopened and solved more than one times. So the report will look something like this:

solve time                agent name           incident_ref

18:00               A                   240723-000001

13:00               B                   240723-000001

15:00               C                   240723-000001

I'm struggling to let report only shows B the first agent who solve the incident.

trying to use first(transactions.created_by,incidents.closed) or first(transactions.created_by, threads.entered) but it doesn't work.

Code Snippet (add any code snippets that support your topic, if applicable):