The numbering of
the ring carbon atoms start from the carbon atom attached to the
aldehyde group The name of the simplest aromatic aldehyde
carrying 
the 
aldehyde 
group 
on 
a 
benzene 
ring 
is
benzenecarbaldehyde However, the common name benzaldehyde
is also accepted by IUPAC Other aromatic aldehydes are hence
named as substituted benzaldehydes