If ΔABC and ΔGEF are congruent by the ASA criterion, which pair of angles must be congruent?

The corresponding angles must be congruent.
According to normal conventions, if ABC is congruent to GEF (by whatever justification), then angles A &G must be congruent, B & E must be congruent, and C and F must be congruent.
If the convention is not followed, a diagram with all information is required to find the pairs of congruent angles.