cursor = connection.cursor()
cursor.execute("SELECT * FROM TABLE NAME ORDER BY TIME DESC")
result = dict()
while len(result) < 3:
   row = cursor.fetchone()
   if row is None:
        break
   name = row[5] 
   if name not in result:
        result[name] = row 

SELECT * FROM my_table ORDER BY id DESC LIMIT 3 

select DISTINCT(tn.name), tn.id from tablename tn WHERE ROWNUM <= 3 order by tn.id desc;

select top N