You can do this directly in SQL.
Use distinct
to get only records that are no duplicates
SELECT DISTINCT a.NAME
FROM your_table a
WHERE a.NAME = 'JOHN SMITH'
or use top
to get only a certain amount or records as result
SELECT top 1 a.NAME
FROM your_table a
WHERE a.NAME = 'JOHN SMITH'
1
solved Query to get rid of matching records C#