Its 250 unless otherwise directed by ATC until joining up on the LOC and configuring flaps gear exc as appropriate to manage speed reduction to be fully configured and stable at 1000ft AGL as per company procedure. This is especially true AT ORD where they do not want you slowing way out and clogging up the pipes. If ORD TRACON wants you to slow down they will assign you a speed. Other wise keep your speed up to help um out. The CRJ is tough to slowdown and go down and requires you to think 10 steps ahead of the aircraft at all times. In the high pace environments Like ORD,JFK exc you have to be on top of your game. Its a tough environment but can also be a lot of fun. Slowing too far out can land you a phone call.