astroquery.vizier not retrieving selected columns

I discovered astroquery yesterday and I think it is a great tool for me. However, I failed to reproduce the example in the docs when selecting only certain columns from a catalog:
```python
>>> v = Vizier(columns=['_RAJ2000', '_DEJ2000','B-V', 'Vmag', 'Plx'], column_filters={"Vmag":">10"}, keywords=["optical"])

>>> result = v.query_object("HD 226868", catalog=["NOMAD", "UCAC"])

>>> print result
TableList with 3 tables:
        '0:I/297/out' with 21 column(s) and 50 row(s) 
        '1:I/289/out' with 16 column(s) and 18 row(s) 
        '2:I/322A/out' with 26 column(s) and 10 row(s)

>>> print result[2]
 _RAJ2000   _DEJ2000   Vmag    UCAC4      RAJ2000   ...  Z   B   L   N   S 
   deg        deg      mag                  deg     ...                    
---------- ---------- ------ ---------- ----------- ... --- --- --- --- ---
299.572419  35.194234 15.986 626-088995 299.5724189 ...   0   0   0   1   0
299.580291  35.176889 13.274 626-089002 299.5802912 ...   1   0   0   3   0
299.582571  35.185225 14.863 626-089007 299.5825712 ...   0   0   0   1   0
299.594172  35.179995 14.690 626-089015 299.5941718 ...   0   0   0   1   0
299.601402  35.198108 14.644 626-089019 299.6014021 ...   1   0   0   0   0
299.617669  35.186999 14.394 626-089038 299.6176686 ...   1   0   0   1   0
299.561498  35.201693 15.687 627-087872 299.5614977 ...   0   0   0   3   0
299.570217  35.225663 14.878 627-087887 299.5702165 ...   0   0   0   3   0
299.601081  35.233338 13.170 627-087924 299.6010806 ...   1   0   0   1   0
299.617995  35.205864 13.946 627-087944 299.6179950 ...   1   0   0   1   0
```
Is this a bug or am I doing something wrong?

Thanks in advance for your help!