Show ip dhcp pool

shows you the leased DHCP IP addresses.
2811#sh ip dhcp pool

Pool sdm-pool1 :
Utilization mark (high/low) : 100 / 0
Subnet size (first/next) : 0 / 0
Total addresses : 254
Leased addresses : 54
Pending event : none
1 subnet is currently in the pool :
Current index IP address range Leased addresses
10.1.1.163 10.1.1.1 - 10.1.1.254 54
2811#