comparatively both are most important. Normally CATIA in Design software and ANSYS is simulation software. now you might one question in your mind i know CATIA also used for simulation but compare to the ANSYS is very low effective and take long time. so My opinion is ANSYS is best for design and simulation. Now a days most of the industry used ANSYS Work Bench for different Design and modelling and simulation purpose..
CATIA is PLM software, In industry, catia has mainly used for surface modelling and sheet metal product modeling. ...
Ansys is one of the engineering simulation (CAE) software.. product’s stress concentration and load distribution areas can be analysed using Ansys software.
Ansys APDL suggested for accurate results in numerical analysis