Both are correct and mean the same thing. This page from the Oxford Learners' Dictionary will help you and some other members. It gives the verbs most often used with "decision": http://www.oxfordlearnersdictionaries.com/definition/english/decision

"To take a decision" is very widely used in the UK. See this press release from the Labour Party for an example: QUOTE Jon Ashworth MP, Labour's Shadow Cabinet Office Minister, responding to Tim Farron's interview in today's Times, said: "Tim Farron is right to say the Lib Dems should be judged on 'everything they've been doing' in Government. Along with the Tories they have delivered a cost-of-living crisis while cutting taxes for millionaires, trebled tuition fees after opposing an increase in opposition, and raised VAT after campaigning against a rise. "They took the decision to prop up David Cameron and they share the blame for this failed Tory-led Government. You can't trust a word the Lib Dems say." UNQUOTE

It's always a great idea to check the dictionary, as Ben suggests. In America, we always say "make a decision," and I notice that Ruthi, from the UK, says that as well.

No we always say to "make a decision" not to take a decision.

One more example of the use of "take a decision" (in the UK), from David Cameron's statement to the media at Downing Street following the outcome of the Scottish Independence Referendum. "Let us first remember why we had this debate—and why it was right to do so. The Scottish National Party was elected in Scotland in 2011 and promised a referendum on independence. We could have blocked that, we could have put it off but just as with other big issues, it was right to take—not duck—the big decision."