If you want to find out siebel crm version, you can get the information from S_APP_VER table.
SQL> select app_ver from siebel.S_APP_VER;
If you want to know applied patch version, go to siebel installed server under the directory of
[root@siebelapps upgrade]# cat base.txt
18.104.22.168 SIA  LANG_INDEPENDENT patch applied.