Article 90, Chapter 3 of the Civil Code of the Philippines

Art. 90. When a marriage is annulled, the court shall award the custody of the children as it may deem best, and make provision for their education and support. Attorney's fees and expenses incurred in the litigation shall be charged to the conjugal partnership property, unless the action fails. 

 Explanations:

In an Action for Annulment of Marriage, the following marriages may be annulled:

1. that the party in whose behalf it is sought to have the marriage annulled was eighteen years of age or over, but below twenty-one, and the marriage was solemnized without the consent of the parents, guardian or person having substitute parental authority over the party, in that order, unless after attaining the age of twenty-one, such party freely cohabited with the other and both lived together as husband and wife;
2. that either party was of unsound mind, unless such party after coming to reason, freely cohabited with the other as husband and wife;
3. that the consent of either party was obtained by fraud, unless such party
   afterwards, with full knowledge of the facts constituting the fraud, freely
   cohabited with the other as husband and wife;
4. that the consent of either party was obtained by force, intimidation or undue influence, unless the same having disappeared or ceased, such party thereafter freely cohabited with the other as husband and wife;
5. that either party was physically incapable of consummating the marriage with the other, and such incapacity continues and appears to be incurable; or
6. that either party was afflicted with a sexually-transmissible disease found to be serious and appears to be incurable.

The appropriate remedy for these grounds is an action for the annulment of
marriage. Unlike in the first set of grounds above mentioned, an action for the annulment of marriage prescribes; in case of lack of consent, until the party filing for annulment reaches 21;  in case of insanity until the death of either party or the lucid interval of the insane spouse; in case of fraud, force, intimidation or undue influence, incapacity to consummate the marriage or knowledge of the sexually-transmissible disease, within five years from the occurrence of the fraud, force, intimidation or undue influence, incapacity to consummate the marriage or knowledge of the sexually-transmissible disease.

  

In this article it says that education is important to the children.Although the parents were annulled  they should have the responsibility to give the support and education for their children.