From the rulebook
Quote:
If all of the units in the defending formation have been killed
and at least one attacker survives, then the attacker wins and
the assault is over (go straight to 1.12.8 ). If all of the attacking
units directly engaged in the assault are killed then the assault
has stalled and the defender wins (go straight to 1.12.8 ).
'Directly engaged' means being within 15cm of a defending
unit after charge and counter-charge moves have been
completed. If even one of the original attackers that were
within 15cms of the enemy survives, then the attack has not
stalled. In any other case, both sides can call on support (see
1.12.6).
With a draw both sides would counter charge and carry on until a winner is decided.
FAQ answer
Quote:
1.12.7 Work Out Result
Q: What happens if a combat round in
an Assault is a draw, do you
immediately fight another round? And
this round is also a draw do you fight a
third successive round (and so on)?
A: Yes. An Assault has to result in one side
winning. You would continue to fight
Assaults until one side or the other had
won the Assault.
Quote:
Q: In a game we have an Assault that
results in a tie. Consequently we must
fight another round of combat. Both
sides do their counter-charge move
but at the end of the move neither
formation has any units within 15cm
of an enemy unit. Do we resolve this
round of combat (even though no
casualties could be caused) or is the
Assault consider over because there
are no units within 15cm of an enemy
unit?
A: You would need to resolve the new
Assault round, even though no actual
fighting took place. So work out the results
as per 1.12.7 and don't forget to include
the casualties from the first round of the
Assault when determining the winner of
this second round.