DHCP client behaviour when there is local DHCP server and also DHCP relay to centralized DHP server

Is it possible to force clients to use local DHCP server rather than be forwarded to a central DHCP via DHCP relay configured on router ?  what is default behaviour will local DHCP always acknowledge DHCP requests before the central one ?  is it just down to which server is quickest to respond ?  I want to force the clients to use local DHCP.