Instances minus duplicates

I have a column of names, several of which appear more than once.

For example:

John Doe
John Doe
Jane Dickenson
Xavier James

In the adjacent column I would like a numeric output of either 1 or 0. I would like 1 to appear for the first instance of a name occurrence and a 0 for any repeated instances of the name, so I can sum the number of people in the column, not the number of instances they appear. So to correspond to the four names above, in the adjacent column I would like to see:

1
0
1
1

Thanks for the help!

--David