The Sensex at the Bombay Stock Exchange today rose 13 points in early trade extending gains for the second straight session. The gain came following sustained buying by funds in bluechips amid a firm trend in the Asian region. The 30-share index, which had gained 88 points in the previous session, rose further by 13 points to 18,642 points, led by oil and gas, power and IT sector stocks.The National Stock Exchange index Nifty moved up by 11 points to 5,620 points.In Asia, Hong Kong's Hang Seng index rose by 1.18 per cent, while Japan's Nikkei by 1.41 per cent in early trade.The US Dow Jones Industrial Average ended 0.69 per cent higher in yesterday's trade.