Unless specified otherwise*, all bets placed refer to the result at the end of "Regular Time" or "Full Time" only.
"Regular Time" or "Full Time" is defined by the official rules from the respective governing association. For example:
Football: full time 60 minutes (4 x 15 minutes).
Ice hockey: full time 60 minutes (3 x 20 minutes).
An exception would be if the governing association specifies that the event will be played over a different duration (for example, a regulation baseball game is 9 innings, but if there is bad weather, a game may be ruled officially over and a winner decided with just a minimum of 4.5 innings having been played). This change will still only include "regular" playing time and not any extension such as extra time or overtime, unless explicitly stated.
*if your bet is valid for a different time period, this will be stated in conjunction with the bet offer, or in the sport specific rules.