Joko 'Jokowi' Widodo, the highly popular Governor of Jakarta, is the PDI-P's presidential candidate for the July presidential election. The position of vice-presidential candidate is still vacant however. During the election, the president and vice-president will run as a fixed, inseparable pair, which implies that the composition of this pair is of great political strategic importance. A political party needed to win at least 25 percent of the vote or 20 percent of seats in the 560-seat House of Representatives (DPR) in order to be able to nominate a presidential and vice-presidential candidate. As no party could meet this threshold, parties thus need to form coalitions now. The winner of the legislative election (PDI-P) could only secure about 19 percent of the popular vote.

The Central Executive Board Chairman of the PKB, Marwan Jafar, said that Muhaimin Iskandar and Mahfud M.D. are the potential contenders for the position of Jokowi's running mate. The PKB is closely related to Indonesia's largest Moslim organization, the Nahdlatul Ulama (NU). Previously, officials of the Nasdem party suggested Jusuf Kalla as the most suitable running mate for Jokowi.

The possible coalition between the PDI-P and PKB is expected to be announced soon.

Meanwhile, Soeharso Monoarfa - Vice Chairman of the PPP - was reported to have had a meeting with PDI-P Chairwoman Megawati Soekarnoputr in order to discuss a possible cooperation between the PDI-P and PPP as the latter is also backs Jokowi as presidential candidate. However, former PPP Chairman Hamzah Haz said that these talks only aim at a cooperation, not at a coalition.

Parliamentary Elections 1999-2014:

     2014¹    2009    2004    1999
 PD    10.0%    20.8%     7.5%        -
 Golkar    15.0%    14.5%    21.6%    22.4%
 PDI-P    19.0%    14.0%    18.5%    33.7%
 Gerindra    12.0%     4.5%        -        -
 PKB     9.1%     4.9%    10.6%    12.6%
 PKS     6.9%     7.9%     7.3%     1.4%
 PAN     7.7%     6.0%     6.4%     7.1%
 NasDem     6.6%        -        -        -
 PPP     6.3%     5.3%     8.2%    10.7%

¹ based on quick counts, not the official result

Further Reading:

 Analysis of Quick Count Results of the Indonesian Legislative Election 2014
Can Joko Widodo Accelerate the Democratization Process in Indonesia?
The Jokowi Effect: Indonesia's Financial Markets Gain on Political Certainty
An Overview of Indonesia's Reformation Period
Politics of Indonesia