There are basically two types of time limits in the sport of baseball and softball.
REGULAR/BASIC TIME LIMIT
The key aspect of this type of time limit is that no new inning will start once the time limit expires. So, for example, if the time limit is 1 hour and 20 minutes and the last out is made by the home team with any time left in the time limit (ie: 1 hour 17 minutes) then they will start a new inning. if the time limit expired before the last out by the home team then the game will be over based on the time limit.
There are some exceptions such as a tie game or when the home team is not able to score enough to win.
DROP DEAD TIME LIMIT
The Drop Dead Time Limit is a pure time limit where the game is over at the point the time limit expires.