When opposed to the dealer the question of correct second-hand play
is relative to your position at the table. That is whether you play
before the dummy or before the dealer. In other words, whether the
dummy is at your left or whether the dealer is at your left.
If you will try to infer why the dealer is leading that suit, it
will assist you to decide on the correct second-hand play. It is, of
course, reasonable to suppose that he has some strength in the suit.
What this strength may be you must judge from the cards that you hold
and those that you see on the table.