IMHO .... white will work --- deep pond OR lake.
Just remember that the light is not used to draw in the Crappie, but the baitfish minnows/shad that come to feed on the zooplankton that the light draws. The "baitfish" feeding activity (sound) attracts the Crappie. So if there's no real population of baitfish in the pond, lights may not be as important a factor in drawing the fish to you.
... cp