Sharing a yaxis label with two of three subplots in pyplot

I have the following code which produces the plot shown.

mport matplotlib.pyplot as plt 
import matplotlib.gridspec as gridspec
import numpy as np

One = range(1,10)
Two = range(5, 14) 
l = len(One)
fig = plt.figure(figsize=(10,6))
gs = gridspec.GridSpec(3, 1, height_ratios=[5, 3, 3]) 

ax0 = plt.subplot(gs[0])
ax0.bar(range(l), Two)
plt.ylabel("Number of occurrence")

ax1 = plt.subplot(gs[1], sharey=ax0)
ax1.bar(range(l), Two)

ax2 =  plt.subplot(gs[2])
ax2.bar(range(l), One)

plt.show()

I want the ylabel (" Number of occurrence") to be shared between first and second plot, that is, it should occur in the center left of first and second plot. How do I do that?