For ISIS the router with the highest ISIS system ID (Router ID in show cmd) will be the active one.
RP/0/0/CPU0:R5#sh isis segment-routing prefix-sid-map active-policy det
Fri Jun 9 09:44:38.761 UTC
IS-IS CORE active policy
Prefix
1.1.1.1/32
Source: Remote
Router ID: 0000.0000.0002
Level: 2
SID Index: 101
Range: 1
Last Prefix: 1.1.1.1/32
Last SID Index: 101
Flags: