Jason is correct. This information will not be found in the DB. You can however bump the Discovery Server to log level 5 and get this information. You will want to pay attention to these three log entries.
june 30 00:09:57:493 WARN [scanTask-4, discovery_server] 2 active robots have the same robot_device_id: 'XYZ'.
june 30 00:09:57:493 WARN [scanTask-4, discovery_server] Keeping robot '/domain/hubA/robotA'. IP: '1.1.1.7'. Created time: '1433940170'.
june 30 00:09:57:493 WARN [scanTask-4, discovery_server] Ignoring robot '/domain/hubA/robotB'. IP: '1.1.1.6'. Created time: '1433940170'.