create table marxBrothers (
    ident int IDENTITY,
    Name varchar(32)
)
go
insert marxBrothers (Name)
    select 'Groucho Marx' UNION ALL
    select 'Harpo Marx' UNION ALL
    select 'Chico Marx' UNION ALL
    select 'Groucho Marx' UNION ALL
    select 'Harpo Marx' UNION ALL
    select 'Chico Marx' UNION ALL
    select 'Zeppo Marx' UNION ALL
    select 'Gummo Marx' UNION ALL
    select 'Zeppo Marx'
    
select * from marxBrothers
delete marxBrothers
from marxBrothers,
    (
        select min(ident) as minIdent, name
        from marxBrothers m
        group by name
        having count(1) > 1
    ) as derived
where marxBrothers.name = derived.name
-- This 'and' makes sure that one of the duplications is not deleted, 
-- remove it if you do not want one copy of the duplication to remain.
and ident > minIdent

select * from marxBrothers...