OSPF DR and BDR election is based on the higher Router ID if priority is equal.
The router ID = the highest loopback address
If there is no loopback address router ID = the highest physical address.
In your question
Rtr 1 ID = 192.168.0.1
Rtr 2 ID = 192.168.0.6
Rtr 3 ID = 188.8.131.52
Therefore DR = 192.168.0.6
BDR = 192.168.0.1
Notice that DR and BDR election process is not repeated when new address is configured. For example if DR = 192.168.0.6 and BDR 192.168.0.1 and you configure new loopback address in RT1 = 192.168.255.255 the DR and BDR will not change until you clear OSPF process or restart the router. Loopback addresses are used because they are logical addresses that they don’t shut down unlike physical addresses.