The airspeed is whatever the turbulence N1 gives you.
I would assume it works out at roughly .76 in still air as it is normally showing a bit lower than the N1 required for econ cruise (just try it in the cruise when there is no turbulence, it won't bite. Or in the sim if you're not happy trying these things for real), but the whole point with turbulence penetration in the cruise is that there is no target airspeed. No target means no target to chase.