@Imran Shad
The bad news is that you cannot use the updated field (sys_updated_on) since another modification to the ticket could have been done (not on the status field) and that date stamp won't represent "when the ticket went to the on-hold state".
The only EXACT way of answering your question is by having a METRIC on the incident and sc_req_item tables to track the STATE field (very simple). There is an out of the box for incident that most likely is already doing that (screen below). Just add this to your instance to see it: /metric_definition.do?sys_id=35f2b283c0a808ae000b7132cd0a4f55
You can create one for the sc_req_item table too.
Then you would use the out of the box database views, incident_metric and sc_req_item_metric, to report. They combine the information from the ticket fields and the metric fields.
