Not in HO scale, Carol. To convert a real-world dimension to HO scale, simply divide by 87. So . . .
12"/87 = 0.137" (to the nearest 1/1000")
Therefore, in HO scale, you could use 1/8" (0.125") tubing to represent a 12" pole. The 1/8" tubing would be slightly undersized, but I doubt if anyone...