Question: The political party Gerry Mullan belonged to currently has how many MLAs in the Northern Ireland Assembly?

Context paragraphs:
Speaker of the Northern Ireland Assembly: The Speaker of the Northern Ireland Assembly (originally having the title of Presiding Officer) is the presiding officer of the Northern Ireland Assembly, elected on a cross-community vote by the Members of the Northern Ireland Assembly.  A Principal Deputy Speaker and two Deputy Speakers are elected to help fulfil the role.  The office of Speaker is currently held by DUP MLA, Robin Newton.

Gerry Mullan (politician): Gerry Mullan (born 24 September 1954) is a former Social Democratic and Labour Party (SDLP) politician from Northern Ireland.

1937 Social Credit backbenchers' revolt: The 1937 Social Credit backbenchers' revolt took place from March to June 1937 in the Canadian province of Alberta.  It was a rebellion against Premier William Aberhart by a group of backbench (not part of the cabinet) members of the Legislative Assembly (MLAs) from his Social Credit League.  The dissidents were unhappy with Aberhart's failure to provide Albertans with C$25 monthly dividends through social credit as he had promised before his 1935 election.  When the government's 1937 budget made no move to implement the dividends, many MLAs revolted openly and threatened to defeat the government in a confidence vote.

NI21: NI21 was a short-lived political party in Northern Ireland.  It was founded in 2013 by ex-Ulster Unionist Party MLAs Basil McCrea and John McCallister.  Although it explicitly supported Northern Ireland staying part of the United Kingdom (i.e. unionism), it planned to designate as "other" rather than "unionist" in future Stormont elections.  It presented itself as a "cross-community party" and promoted a Northern Irish national identity for the 21st century.  The party had two MLAs in the Northern Ireland Assembly and a single Councillor in Lisburn and Castlereagh City Council before crisis.

Northern Ireland Assembly election, 2017: The 2017 election to the Northern Ireland Assembly was held on 2 March 2017.  The election was held to elect members (MLAs) following the resignation of deputy First Minister Martin McGuinness in protest over the Renewable Heat Incentive scandal.  McGuinness' position was not filled, and thus by law his resignation triggered an election.  It was the sixth election since the Assembly was re-established in 1998, and the first to implement a reduction in size to 90 MLAs (versus the previous 108).

Social Democratic and Labour Party: The Social Democratic and Labour Party (SDLP; Irish: "Páirtí Sóisialta Daonlathach an Lucht Oibre" ) is a social-democratic and Irish nationalist political party in Northern Ireland.  The SDLP currently has 12 MLAs in the Northern Ireland Assembly; but lost its three remaining Parliamentary seats in the 2017 general election.

Northern Ireland Unionist Party: The Northern Ireland Unionist Party (NIUP) was a small political party in Northern Ireland.  It was formed in January 1999 as a splinter party from the UK Unionist Party (UKUP).  This split was caused by disagreement between the five UKUP members of the Northern Ireland Assembly.  Four of the members disagreed with UKUP leader Robert McCartney's policy of resigning from the Assembly should Sinn Féin become part of the power-sharing executive.  Cedric Wilson, Patrick Roche, Norman Boyd and Roger Hutchinson disagreed with McCartney, wanting to remain in the Assembly to challenge unionists in favour of the Belfast Agreement.  McCartney disciplined these members in their absence and, in response, they left the UKUP and formed the NIUP.  Led by Wilson, the new party argued that it had the support of the grassroots membership of the UKUP, but McCartney disputed this.

Northern Ireland Assembly Commission: The Northern Ireland Assembly Commission (usually referred to as the Assembly Commission) is the corporate body of the Northern Ireland Assembly.  The commission is headed by the Speaker of the Northern Ireland Assembly, currently Mitchel McLaughlin MLA.

Stewart Dickson: Stewart Dickson is an Alliance Party of Northern Ireland politician and was a member of the Northern Ireland Assembly, where he represented East Antrim.  He sought re-election on the 2nd of March 2017 in a snap election that was called to the Renewable Heat Incentive (RHI) scandal and was re-elected to the Assembly as one of five MLAs for this constituency.

Politics of Northern Ireland: Since 1998, Northern Ireland has devolved government within the United Kingdom.  The government and Parliament of the United Kingdom are responsible for reserved and excepted matters.  Reserved matters are a list of policy area (such as civil aviation, units of measurement, and human genetics), which the Westminster Parliament may devolve to the Northern Ireland Assembly at some time in future.  Excepted matters (such as international relations, taxation and elections) are never expected to be considered for devolution.  On all other matters, the Northern Ireland Executive together with the 108-member Northern Ireland Assembly may legislate and govern for Northern Ireland.  Additionally, devolution in Northern Ireland is dependent upon participation by members of the Northern Ireland Executive in the North/South Ministerial Council, which co-ordinates areas of co-operation (such as agriculture, education and health) between Northern Ireland and the Republic of Ireland.

Supporting paragraphs: Gerry Mullan (politician) Social Democratic and Labour Party
Answer: 12