* TSX up 6.38 points, or 0.04 percent, at 14,308.44 * Five of 10 main index sectors advance * CP Rail slips after share buyback plan By John Tilak TORONTO, March 11 (Reuters) - Canada's main stock index was little changed in choppy trading on Tuesday as concerns about the crisis in Ukraine were offset by a jump in gold-mining shares after the price of bullion gained. Ukraine's interim leaders formed a new National Guard and appealed to the United States and Britain for assistance against what they called Russian aggression in Crimea. Those worries sent investors scurrying for safety in commodities such as bullion, which climbed and helped send shares of gold producers higher. Gains in the gold-mining sector, which is up about 29 percent this year, have fueled the broader Canadian market in recent weeks. The benchmark index has gained about 5 percent in 2014, outperforming the S&P 500, but that has some investors concerned about a potential market pullback. "North American equity markets are looking a bit extended," said Stan Wong, director of wealth management and portfolio manager at Scotia McLeod. "I wouldn't be surprised if we took a pause here. "The upcoming referendum in Crimea will undoubtedly (raise) some investor anxiety about geopolitical tensions in that region." The Toronto Stock Exchange's S&P/TSX composite index was up 6.38 points, or 0.04 percent, at 14,308.44. Five of the 10 main sectors on the index were higher. "Markets in general are not cheap," Wong said. "At this point it's a stock picker's market, and we will need more data towards continued economic growth to push equity markets to higher highs." His top picks include Baytex Energy Co, Telus Corp and Manulife Financial Corp. Goldcorp Inc jumped 1 percent to C$29.87, and Barrick Gold Corp climbed 0.6 percent to C$22.02. Those moves pushed the gold-mining sector up more than 1 percent. Financials, the index's most heavily weighted sector, added 0.2 percent, with Toronto Dominion Bank rising 0.6 percent to C$51.32 and Bank of Montreal advancing 0.6 percent to C$72.80. In corporate news, Canadian Pacific Railway Ltd said it planned to buy back up to 5.3 million shares over the next year. The stock slipped 1.2 percent to C$169.27, weighing on the broader industrial sector.