How do I eliminate the duplicate rows ?

SQL> delete from table_name where rowid not in (select max(rowid) from table group by
duplicate_values_field_name);
or
SQL> delete duplicate_values_field_name dv from table_name ta where rowid <(select min(rowid) from
table_name tb where ta.dv=tb.dv);
Example.
Table Emp
Empno Ename
101      Scott
102       Jiyo
103      Millor
104      Jiyo
105      Smith
delete ename from emp a where rowid < ( select min(rowid) from emp b where a.ename = b.ename);
The output like,
Empno Ename
101      Scott
102      Millor
103      Jiyo
104     Smith