TORONTO -- Ontario Premier Kathleen Wynne faced off against Progressive Conservative Leader Tim Hudak and NDP Leader Andrea Horwath in the leaders' election debate Tuesday night.

Five things you need to know about the debate:

1. Gas plants scandal

The Liberal government's decision to cancel two gas plants ahead of the 2011 election was front and centre at the leaders' debate. Progressive Conservative Leader Tim Hudak and New Democrat Leader Andrea Horwath pressed Premier Wynne to explained why she went along with the government decision, which could end up costing taxpayers $1.1 billion. Wynne apologized several times and said she's taken action to make sure that the same mistake doesn't happen again. Both Hudak and Horwath said the Liberals can't be trusted, with the NDP leader saying "corruption runs deep" in the Liberal party.

2. Million Jobs pledge

Hudak made a bold pledge during the debate: He would resign as premier if doesn't keep the promises in his Million Jobs Plan. Hudak later told reporters that he would step down if he did not eliminate the deficit in two years and that he would balance the books even if the province was hit by another recession.

3. Bad Math

Although Hudak came frequently under attack from the other two leaders over the math behind his plan to create one million jobs over eight years, voters who have not followed the election campaign closely would have been left in the dark about the questions raised by some economists. Horwath said the Tory Million Jobs Plan had "a million mistakes in it," while Wynne asked Hudak to apologize for the bad math but neither provided any details.

4. Transit and Transportation

Hudak tried to portray the Liberals as a party that only caters to the urban centres, mostly the Greater Toronto Hamilton Area. Hudak said Wynne's government was pitting one part of the province against the other and promised his party would be fair and make sure that small town Ontario would prosper alongside big cities such as Toronto, Hamilton and Ottawa.

5. Leaders' performance

Despite claims by all three parties that their leaders had won the debate, political observers said they were not impressed with their performance. They said all three leaders missed good opportunities to highlight their platforms or go after their rivals' controversial election promises. The observers said that for the average undecided voter there wasn't much to take away from the debate.