Which column should i select for Index creation - response (3) by quest

I have 2 amps and have a table of 4 columns col1,col2,col3 and col4.
Following is the ouput of hashamp query. As can  be seen except col1, other columns distribute row across amps appropriately. But what should be derived for col1?

Column Name

Amp #

Row count

Col1

0

58

Col1

1

43

Col2

0

54

Col2

1

47

Col3

0

47

Col3

1

54

Col4

0

50

Col4

1

51