Database Backup compression
Your case statement is wrong. Right now if the values are the same then it shows compressed whereas you would want it to show not compressed.

select top(10) database_name, 
case when  backup_size = compressed_backup_size then 'Not compressed'
else 'Compressed'
end as Compression, 
backup_finish_date
from msdb.dbo.backupset
where database_name ='MyDAtabase'
order by backup_start_date desc