Try this,

This will delete all records where path ='C:\my\'

delete temp where path ='C:\my\' and id (select min(id) from temp where path ='C:\my\' )

To get Third highest value..

Try this..

SELECT MAX(col_name) FROM Table1 A

WHERE 3 = (SELECT COUNT(*)+1 FROM Table1 B WHERE A.Col_name< B.Col_name)